1. Field of the Invention
Embodiments relate to a protective circuit module and a rechargeable battery including the same.
2. Description of the Related Art
A rechargeable battery is a battery capable of repeated recharging and is recently attracting a great deal of attention for its wide applicability to a variety of electronic equipment due to convenient portability and rechargeability. A rechargeable battery, e.g., a square-type rechargeable battery, may be composed of a bare cell including a generally square can, an electrode assembly housed inside the can, and a cap assembly connected to an opening for inserting the electrode assembly into the can.
The bare cell may be electrically connected to a protective circuit board to control charge/discharge of the rechargeable battery. A safety device, e.g., a positive temperature coefficient (PTC) device, a thermal fuse, or the like, may be disposed between the bare cell and the protection circuit board.
The safety device may be connected to at least one electrode terminal of the bare cell and may be adjacent to the bare cell to thereby cut off the current flow from the bare cell to the outside when the battery temperature rises or a voltage of the battery rises above a given value due to excessive charge/discharge. That is, the safety device may serve to prevent damage or deterioration of the battery that may occur when the battery is exposed to high temperature and/or overvoltage conditions.
A PTC device may be installed on the protective circuit board to form a protective circuit module. The PTC device may prevent the flow of electric current upon the occurrence of elevated temperature in the protective circuit board, thus ensuring safety of the battery. This PTC device may be a chip-type PTC device. The chip-type PTC device may have advantages, e.g., ease of installation, low cost, and the like.
The chip-type PTC device may be installed on the protective circuit board, spaced apart from the bare cell. As a result, the temperature-detecting performance of the chip-type PTC device may deteriorate when the temperature of the bare cell is elevated. That is, the chip-type PTC device may fail to directly detect heat generated from the bare cell and therefore may not reliably perform its protective functions.